LXR linux/arch/arm/mm/copypage-v6.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/arch/arm/mm/copypage-v6.c
   4 *
   5 *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
   6 */
   7#include <linux/init.h>
   8#include <linux/spinlock.h>
   9#include <linux/mm.h>
  10#include <linux/highmem.h>
  11
  12#include <asm/shmparam.h>
  13#include <asm/tlbflush.h>
  14#include <asm/cacheflush.h>
  15#include <asm/cachetype.h>
  16
  17#include "mm.h"
  18
  19#if SHMLBA > 16384
  20#error FIX ME
  21#endif
  22
  23static DEFINE_RAW_SPINLOCK(v6_lock);
  24
  25/*
  26 * Copy the user page.  No aliasing to deal with so we can just
  27 * attack the kernel's existing mapping of these pages.
  28 */
  29static void v6_copy_user_highpage_nonaliasing(struct page *to,
  30        struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  31{
  32        void *kto, *kfrom;
  33
  34        kfrom = kmap_atomic(from);
  35        kto = kmap_atomic(to);
  36        copy_page(kto, kfrom);
  37        kunmap_atomic(kto);
  38        kunmap_atomic(kfrom);
  39}
  40
  41/*
  42 * Clear the user page.  No aliasing to deal with so we can just
  43 * attack the kernel's existing mapping of this page.
  44 */
  45static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  46{
  47        void *kaddr = kmap_atomic(page);
  48        clear_page(kaddr);
  49        kunmap_atomic(kaddr);
  50}
  51
  52/*
  53 * Discard data in the kernel mapping for the new page.
  54 * FIXME: needs this MCRR to be supported.
  55 */
  56static void discard_old_kernel_data(void *kto)
  57{
  58        __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  59           :
  60           : "r" (kto),
  61             "r" ((unsigned long)kto + PAGE_SIZE - 1)
  62           : "cc");
  63}
  64
  65/*
  66 * Copy the page, taking account of the cache colour.
  67 */
  68static void v6_copy_user_highpage_aliasing(struct page *to,
  69        struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  70{
  71        unsigned int offset = CACHE_COLOUR(vaddr);
  72        unsigned long kfrom, kto;
  73
  74        if (!test_and_set_bit(PG_dcache_clean, &from->flags))
  75                __flush_dcache_page(page_mapping_file(from), from);
  76
  77        /* FIXME: not highmem safe */
  78        discard_old_kernel_data(page_address(to));
  79
  80        /*
  81         * Now copy the page using the same cache colour as the
  82         * pages ultimate destination.
  83         */
  84        raw_spin_lock(&v6_lock);
  85
  86        kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
  87        kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
  88
  89        set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
  90        set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
  91
  92        copy_page((void *)kto, (void *)kfrom);
  93
  94        raw_spin_unlock(&v6_lock);
  95}
  96
  97/*
  98 * Clear the user page.  We need to deal with the aliasing issues,
  99 * so remap the kernel page into the same cache colour as the user
 100 * page.
 101 */
 102static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 103{
 104        unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 105
 106        /* FIXME: not highmem safe */
 107        discard_old_kernel_data(page_address(page));
 108
 109        /*
 110         * Now clear the page using the same cache colour as
 111         * the pages ultimate destination.
 112         */
 113        raw_spin_lock(&v6_lock);
 114
 115        set_top_pte(to, mk_pte(page, PAGE_KERNEL));
 116        clear_page((void *)to);
 117
 118        raw_spin_unlock(&v6_lock);
 119}
 120
 121struct cpu_user_fns v6_user_fns __initdata = {
 122        .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 123        .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 124};
 125
 126static int __init v6_userpage_init(void)
 127{
 128        if (cache_is_vipt_aliasing()) {
 129                cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 130                cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 131        }
 132
 133        return 0;
 134}
 135
 136core_initcall(v6_userpage_init);
 137